Once upon a time, I used to commute to Silicon Valley and carried around a bag with my laptop, paperwork, and other items.  I tried various kinds of bags, including a fashion shoulder bag, a messenger bag and finally a backpack.

I’m pleased to report that my little personal experimentation concurs with research on the topic.  It’s easier to carry a messenger bag than a shoulder bag, but even easier to carry a backpack.  Research actually says that the energy needed to carry a shoulder bag is 2.4 times more than for a backpack, and carrying a messenger bag requires 1.8 times more energy than a backpack.  In addition, shoulder and messenger bags force a postural correction to compensate for the asymmetry of the load.  Notice people around you with shoulder or messenger bags. You’ll see the carrying shoulder typically riding higher than the other or people leaning to the opposite side of the load being carried, especially when carrying a handbag or briefcase.

But even after trading my fancy-looking shoulder bag for a backpack, I continued to notice discomfort in my back, shoulders and neck.  That’s when I decided to get on the scale with my backpack.  The number I saw was unbelievable — and no, it wasn’t because of the extra ice cream I’d gulped down that summer.  My backpack was way too heavy for me.

Your backpack should weigh no more than 15% of your body weight, and never more than 25 lbs.  So if you weigh 125 lbs., your backpack should weigh no more than 18 lbs. (which is still feels heavy). If you’re 165 lbs. or 200 lbs., your backpack should weigh no more than 25lbs.  You should also pack heavier items closer to your back.

Weigh yourself with and without your backpack (or purse, as a matter of fact, because some purses out there are way too heavy) and lighten up the load.  You probably don’t really need to carry all those items and your body will thank you.

Now, I don’t have kids (… not yet), but it drives me crazy to see little people carrying big heavy backpacks.  So stay tuned for backpack selection recommendations for both children and grown ups.